1. health and fitness
2. disease
3. diabetes

World J Diabetes 2014 October 15; 5(5): 636-650
ISSN 1948-9358 (online)
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DOI: 10.4239/wjd.v5.i5.636
© 2014 Baishideng Publishing Group Inc. All rights reserved.
REVIEW
Treatment of type 2 diabetes, lifestyle, GLP1 agonists and
DPP4 inhibitors
Gerald H Tomkin
Gerald H Tomkin, Diabetes Institute of Ireland, Beacon Hospital, Sandyford, Dublin 18, Ireland
Gerald H Tomkin, Department of Diabetes and Endocrinology,
Trinity College, Dublin 2, Ireland
Author contributions: Tomkin GH solely contributed to this
paper.
Correspondence to: Gerald H Tomkin, Professor, Diabetes
Institute of Ireland, Beacon Hospital, Sandyford, Clontra, Quinns
Road, Shankill, Dublin 18, Ireland. gerald.tomkin@tcd.ie
Telephone: +353-1-2390658 Fax: +353-1-2721395
Received: January 26, 2014 Revised: July 23, 2014
Accepted: July 27, 2014
Published online: October 15, 2014
Core tip: Treatment of diabetes is difficult. Initial success in achieving treatment goals is followed by deterioration and the necessity for additional treatments.
Exciting new drugs with new modes of action, have
stimulated diabetologists to strive for improved control
in the knowledge that complications will be reduced
or prevented. Obese patients, who loose weight on
glucagon-like peptide-1 agonists are usually delighted
with these drugs but for those who fail to loose weight
changing to oral dipeptidyl peptidase-4 inhibitors would
seem a good choice. sodium-glucose transporter-2 inhibitors have the added benefit of being effective even
if blood sugar is near to target but uro-genital infection
is a concern.
Abstract
Tomkin GH. Treatment of type 2 diabetes, lifestyle, GLP1 agonists and DPP4 inhibitors. World J Diabetes 2014; 5(5): 636-650
Available from: URL: http://www.wjgnet.com/1948-9358/full/
v5/i5/636.htm DOI: http://dx.doi.org/10.4239/wjd.v5.i5.636
In recent years the treatment focus for type 2 diabetes has shifted to prevention by lifestyle change and
to more aggressive reduction of blood sugars during
the early stage of treatment. Weight reduction is an
important goal for many people with type 2 diabetes.
Bariatric surgery is no longer considered a last resort
treatment. Glucagon-like peptide-1 agonists given by
injection are emerging as a useful treatment since they
not only lower blood sugar but are associated with a
modest weight reduction. The role of the oral dipeptidyl peptidase 4 inhibitors is emerging as second line
treatment ahead of sulphonylureas due to a possible
beneficial effect on the beta cell and weight neutrality.
Drugs which inhibit glucose re-absorption in the kidney,
sodium/glucose co-transport 2 inhibitors, may have a
role in the treatment of diabetes. Insulin treatment still
remains the cornerstone of treatment in many patients
with type 2 diabetes.
INTRODUCTION
Readers interested in diabetes must be sick and tired reading that diabetes is a global problem of immense size and
getting worse by the day with predictions that we will all
have the disease one day! I exaggerate of course but it is
sad to realise that although we know so much more about
the condition we have made little progress in reducing or
conquering the disease. A recent history of diabetes in
the past 200 years by Polonsky[1] gives an excellent review
of the history of discovery of so many mechanisms that
are faulty in diabetes and the number of Nobel prize
winners who have contributed to such wonderful success,
yet more and more people are being diagnosed with the
condition/disease and the consequences are immense
in terms of suffering and financial cost. One should not
forget that before the discovery of insulin 90 years ago
© 2014 Baishideng Publishing Group Inc. All rights reserved.
Key words: Type 2 diabetes; Lifestyle modification; Dipeptidyl peptidase 4 inhibitors; Glucagon-like peptide-1
agonists; Insulin
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Tomkin GH. New treatments for type 2 diabetes
diabetes was a rapidly fatal disease and there was little
interest in what we now term type 2 diabetes. Type 2
diabetes now makes up 90% of all diabetes. Insulin resistance rather than insulin deficiency is the major player in
the vast majority of type 2 diabetes and type 2 diabetes
can be reversed, at least in many patients, with exercise
and weight reduction. This is not new information but
was highlighted by Taylor’s group in Newcastle in 2011[2]
when they did a very simple experiment on patients who
had diabetes, were obese and managed with tablets. They
got 13 patients to do what was common practice and
fashionable 40 years ago. They put the patients on an 800
kcal diet, a diet that has been proven beyond doubt to
cause weight loss. Indeed there has never been a report
of anyone who can maintain their weight on an 800 kcal
diet. Compliance was checked by urinary ketones and
weight loss. Eleven of the patients succeeded in finishing
the eight week diet and lost as much weight as would be
expected from bariatric surgery. Just like what happens
following bariatric surgery in patients with type 2 diabetes, the diabetes disappeared and blood pressure and
lipids improved. Nothing spectacular so far and the study
would not have been worthy of reporting since all this
is well known and has been done many times before, as
Professor Yki-Jarvinen in her leading article in Diabetologia[3] wrote “the only problem is that in medical school
and when I was training as an endocrinologist nobody
told me how to get patients to follow such a diet”. Only
10% of patients are able to follow dietary restriction
advice and only the minority take the exercise treatment.
Worse, of those who do succeed 90% relapse. Indeed this
is why low calorie diets became unfashionable and large
type 2 diabetic trials such as the Steino Hospital trial[4]
did not include weight reduction as part of their protocol. The Newcastle group[2] converted an unoriginal and
mundane study into a really exciting study by demonstrating that liver fat almost disappeared completely within a
week and this was associated with a very large improvement in blood sugar and insulin resistance. The rapidity
of improvement was interesting and the significance of
the reduction of fat around the beta cell, a new finding
of uncertain importance. However a plausible theory is
that fat in the vicinity of the beta cell and in particular
cholesterol, may be easily oxidised and the release of free
radicals contributes to damage to the beta cell. In this regard a gene variant Ckal1, a gene associated with protein
translation, has been shown to be very sensitive to oxidation and it is associated with a feeble insulin response[5].
Beta cells have the ability to regenerate and early and
intensive reduction in blood sugar has been shown to improve beta cell function. Hyperglycaemia creates a vicious
circle-the higher the blood sugar the greater the damage
to the beta cell and the greater the damage to the beta
cell the higher goes the sugar. Hence the drive to prevent
hyperglycaemia by intervention in the pre-diabetes phase
and to normalise blood sugar in the early stages of diabetes. The final result of the Newcastle group study that
made me and many others sit up and take notice was the
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demonstration that the beta cell recovered, not partially
but completely, and even the first phase insulin release
returned to normal so the patients really did reverse their
diabetes. This article was of such interest that it made
headlines in daily newspapers around the world. Patients
and their relatives, perhaps for the first time, really understood the damage diabetes does and gained new hope
seeing a goal of reversal of diabetes and the possibility
of discontinuation of diabetes medications. Beta trophin
has been discovered-a hormone expressed mostly in liver
and fat that stimulates beta cell proliferation, expands
beta cell mass and improves glucose tolerance in a mouse
model[6]. Perhaps an exciting new way to help to reverse
diabetes in the future?
The July 2012 edition of the Lancet[7] carried on its
cover “Physical inactivity: Worldwide”, we estimated that
physical inactivity causes 6%-10% of the major noncommunicable diseases. Physical inactivity seems to have
an effect similar to that of smoking or obesity. Min Lee et
al[8] examined how much disease could be averted if inactivity were eliminated. Diabetes, as expected, is one of the
major diseases the authors looked at. They concluded that
not only did physical inactivity account for 6%-10% of
the major non communicable diseases but this unhealthy
behaviour causes 9% of premature mortality. There is
good evidence to demonstrate that overweight or obese
children who become obese as adults are at increased risk
of diabetes whereas overweight or obese children who became non-obese by adulthood are not[9]. More importantly
many studies have shown that educational interventions in
physical activity have actually been successful and indeed
more successful than interventions for obesity. Heath et
al[10] in the same issue of the Lancet, examined interventions from around the world and demonstrate that the
literature is convincing in demonstrating that behavioural
and social approaches are effective. The improvements are
seen among people of various ages and from different social groups, countries and communities. The authors make
the point that although individuals need to be informed
and motivated to adopt physical activity, the public health
priority should be to ensure that environments are safe
and supportive of health and wellbeing.
Since we know so much about the risk of developing
diabetes, it should be possible to have treatment to prevent diabetes in many patients. The diabetes prevention
program outcome study[11] has been recently published.
This ongoing study demonstrated a clear reduction in
diabetes incidence in participants randomly assigned to
a lifestyle intervention or metformin during the intervention period. The authors end by stating that their
data “support early and aggressive measures for long
term prevention of diabetes in people at risk”. Intensive lifestyle intervention has been shown to slow the
decline in mobility in overweight adults with diabetes[12].
A disappointing result has recently come from the Look
AHEAD study[13]. The study was designed to test the
hypothesis that an intensive life style intervention for
weight loss would decrease cardiovascular morbidity and
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Tomkin GH. New treatments for type 2 diabetes
mortality in over weight patients with type 2 diabetes.
More than 5000 patients took part in the study and the
median follow-up of the study was for 9.5 years, weight
loss was modest in the intervention group (6% vs 3.5% at
the end of the study). Alas there was no reduction in the
rate of cardiovascular events. The study results are perhaps not surprising in that significant weight reduction is
unachievable in most patients but does suggest that we as
physicians should accept that most patients are unable to
loose weight and should not be made to feel guilty about
this. On the other hand to continue to engage the patient
in meticulous control of blood pressure, lipids and blood
sugar, together with cessation of cigarette smoking, a
healthy diet and exercise, are of proven benefit.
Casazza et al[14] have written an excellent article entitled “myths, presumptions and facts about obesity”. The
definition of a presumption was a belief in the absence
of supporting scientific evidence; a Myth was defined as
a belief persisting despite contradictory evidence. Facts
were suppositions backed by sufficient evidence to consider them proven for practical purposes. The authors
note that sometimes action is taken by policy makers in
the absence of strong scientific evidence “This principle
of action should not be mistaken as justification for
drawing conclusions”. The myths examined were: (1) that
small sustained changes in energy intake or expenditure
will produce large long term weight changes; (2) Setting
realistic goals for weight loss is important otherwise patients will become frustrated and loose less weight; (3)
Large rapid weight loss is associated with poor long term
weight outcomes as compared with slow gradual weight
loss; (4) It is important to assess the stage of diet readiness in order to help patients who request weight loss
treatment; (5) Physical education courses in their present
form play a part in reducing childhood obesity; (6) Breast
feeding is protective against obesity; and (7) A bout of
sexual activity burns 100-300 cal for each participant.
A stepwise approach to the management of diabetes
has become a fashionable concept in recent years with
many published paradigms of the steps which are variable and often contradictory or display so many different
stairways that they become very confusing. The first step
depends on getting the patient at the very beginning of
their path, that is in the pre-diabetes stage but even then
they may have already suffered from macrovascular and
microvascular damage[15-18]. There is little dissention in
advising the lifestyle changes but, should metformin also
be used or should one wait and see the effect first of the
lifestyle changes? Information on this point is available,
for example in the trial by Snehalatha et al[19] 2009. There
seemed to be no advantage to add metformin to life
style changes so perhaps metformin should be reserved
for those patients who are unable to adhere to life style
changes?
Once diabetes has been diagnosed can one wait and
see the result of life style changes or should one aggressively control blood sugar? High glucose is toxic to the
beta cell. Exciting new information suggests that the
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beta cell may dedifferentiate under high glucose attack by
causing reduction in a key transcription factor, Fox 01.
This dedifferentiation results in the production of inactive proinsulin and an increase in glucagon[20]. Intensive
insulin therapy at diagnosis of type 2 diabetes has been
shown to reverse diabetes. Weng et al[21] studied 382 patients and had divided them into 3 groups. Continuous
insulin infusion, multiple injections or oral agents were
used to achieve rapid normalisation of hyperglycaemia.
Treatment was stopped after normoglycemia was maintained for two weeks. After a year 51% and 44% of the
insulin treated patients were in remission where as only
26% of the patients in the oral agent group had gone
into remission. The evidence to support early and aggressive treatment for type 2 diabetes has not been widely
accepted. The reasons are probably due to a shortage of
personnel to manage patients. In my country there is a
long waiting list to be seen in a diabetic clinic and general
practitioners are usually unhappy about starting insulin.
The better understanding of the beta cell pathology of
diabetes should persuade physicians to adopt a more
urgent approach to diabetes management in the future.
A systematic review and meta-analysis on short term
intensive insulin therapy in type 2 diabetes gives further
support for the ability of this treatment to modify disease
progression[22].
BARIATRIC SURGERY
Bariatric surgery for obese type 2 diabetes has been refined over the last few years. Laparoscopic surgery has
made operation on morbidly obese patients who have
diabetes, and indeed those who do not have diabetes,
much safer and very often will reverse the diabetes. The
operation has been shown to reduce cardiovascular risk.
As with all operations the experience of the surgeon and
indeed the surgical unit plays a very important part in
outcome. A Cochrane review[23] in 2009 concluded that
bariatric surgery is more effective than conventional treatment in achieving and in sustaining weight loss in people
with obesity. Improvements in health related quality of
life and obesity related co morbidities including type 2
diabetes, dyslipidaemia and sleep apnoea are further benefits. A very good review of the subject has recently been
written by Dixon et al[24].
Mingrone et al[25] in 2012 published a single centre
non-blinded randomised controlled trial to examine the
difference in outcome between surgery as compared
to usual medical therapy. Surgery was either gastric bypass or bilio-pancreatic diversion. At the end of 2 years
HbA1c was 6.35% in the gastric bypass group and 4.95%
in the bilio-pancreatic-diversion group as compared to
7.69% in the medically treated group. Diabetes remission
had occurred in 75% of the gastric bypass group and
95% in the bilio-pancreatic diversion group. No patient
in the medical group had reversed their diabetes. There
were no deaths and almost no complications in the surgical group[25].
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In the same edition of the journal Schauer et al[26]
evaluated the efficacy of intensive medical therapy as
compared to medical therapy plus Roux en Y gastric bypass or sleeve gastrectomy in 150 obese patients with uncontrolled type 2 diabetes. The primary end point was the
proportion of patients with a glycated haemoglobin level
of 6.0% or less, 12 mo after treatment. Twelve percent of
the medical group, 42% in the gastric bypass group and
37% in the sleeve gastrectomy group achieved the primary end point. HbA1c was 7.5% in the medical group
6.4% in the gastric bypass group and 6.6% in the sleeve
gastrectomy group. No deaths or life threatening complications occurred[26]. An editorial in the same edition by
Zimmet et al[27] suggests that the bariatric surgery should
not be seen as a last resort. More recently Arterburn et
al[28] did a retrospective analysis to compare rates of diabetes remission, relapse and all cause mortality amongst
severely obese adults with diabetes who underwent
bariatric surgery vs non-surgical treated individuals. At 2
years the surgery subjects had significantly higher diabetes remission rates 73.7% compared to non surgical subjects with 6.9%. The surgical subjects also experienced
lower relapse rates with no higher risk of death[28].
groups in HbA1c. Overall hypoglycaemia was a little less
in the insulin degludec group and nocturnal hypoglycaemia was also a little lower (1.4 vs 1.8 episodes per patientyear exposure). The authors conclude that the newer
basal insulins with lower hypoglycaemia events may allow
more intensive blood sugar lowering treatment. From the
results presented in their paper, insulin degludec does not
seem to be the answer. An editorial by Tahrani et al[33] in
the same edition, ends by saying that insulin degludec is
not a revolution but an evolution of insulin therapy for
patients with both type 1 and type 2 diabetes.
SODIUM GLUCOSE CO-TRANSPORT-2
INHIBITORS
Glycosuria occurs when the blood glucose reaches a
threshold of about 10 mmol/L. However some people
will excrete glucose at much lower levels of blood glucose (renal glycosuria). The discovery that glucose is
transported across the proximal tubule membrane by
sodium/glucose co-transport 2 (SGLT2) and that a
naturally occurring polymorphism of the gene causes
renal glycosuria, paved the way for the development of
SGLT2 receptor inhibitors as a way of promoting renal
glucose excretion and therefore calorie loss and reduction of blood sugar. Two drugs have undergone clinical
trials dapaglifozin and canaglifozin and have been the
subject of a meta analysis by Clar et al[34]. The drugs both
result in blood glucose reduction of about 0.5%-1% with
some weight loss. Urinary and genital infections were
more common. Hypoglycaemia did not occur any more
frequently that placebo. The results of the Cantata-SU
trial have recently been published[35]. The trial was a 52
wk study in type 2 diabetes with patients who were inadequately controlled with metformin. Canagliflozin was
compared to Glimepiride. 1452 patients were randomised
in a phase 3 non-inferiority, double blind, randomised
trial. Three hundred mg of Canagliflozin reduced HbA1c
from a mean of 7.8% to 6.9% (mmol/L) a reduction of
0.9%. Hypoglycaemia was less common on Canagliflozin
and there was a 4 kg reduction in weight with a small
reduction in blood pressure. There was a 0.25 increase in
LDL cholesterol but also a slight, 0.1% increase in HDL
cholesterol and a very slight reduction in triglycerides also
of 0.1%. Genital mycotic infections occurred in 8% in
men and 14% in women on the 300 mg dose. The study
suggests that the benefit of the drug is a useful reduction
in HbA1c and weight reduction. The blood pressure reduction is also of benefit but the rise in LDL might be a
worry and the mycotic genital infections and urinary tract
infections might make the drug unacceptable to many
patients who may have presented with these problems
when first diagnosed. An editorial in the Lancet where
the results were published is entitled “SGLT2 inhibitors
for diabetes: turning symptoms into therapy” and makes
the point that the place of this class of drugs in the treatment of type diabetes is still to be decided[36]. There has
been concern about breast and bladder cancer as well
NEW INSULINS FOR TREATMENT OF
TYPE 2 DIABETES
Many different regimes have been proposed and indeed
are in use for the treatment of type 2 diabetes when life
style and metformin have failed to control hyperglycaemia. A three year efficacy of complex insulins in type
2 diabetes demonstrated that the addition of a basal or
prandial insulin based regimen to oral therapy had better
diabetic control than those who added a biphasic insulin
regimen[29]. My own feeling is that, as so many patients
with type 2 diabetes don’t increase their blood sugars
overnight, attention should be paid to controlling the
post evening meal rise in blood sugar so that the patient
goes to bed with a normal blood sugar, long acting insulins being reserved for those patients in whom blood
sugars rise overnight. To me it doesn’t make sense to give
a basal dose of a long acting insulin pre bed with the risk
of overnight hypoglycaemia to a patient whose blood
sugar has not been shown to rise overnight. Insulin degludec is almost identical to human insulin but with the
last amino acid deleted from the B chain and addition
of a glutamyl link from LysB29 to a hexadecanoic fatty
acid[30]. Two phase 3 studies were reported recently[31,32].
In the first study type 1 diabetic patients (472 subjects)
were subjected to insulin degludec and 157 to glargine
insulin[31]. Although there was no difference in HbA1c
at the end of the study and no difference in overall,
confirmed hypoglycaemia; overnight hypoglycaemia was
25% less in the insulin degludec and of course nocturnal hypoglycaemia is what many patients fear most. The
second study Garber et al[32] reported the effect of the
new insulin in type 2 diabetic patients vs insulin glargine.
Again after 1 year there was no difference between the 2
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Tomkin GH. New treatments for type 2 diabetes
extent as a similar glucose load given orally. It was discovered that hormones secreted from the intestine in response to a glucose load had the ability to release glucose
from the pancreas. These hormones were called incretins
and they are responsible for at least 50% of insulin secretion following a meal. In 1971 a peptide was isolated
from the intestine which had the ability to inhibit gastric
acid secretion and was therefore called gastric inhibitory
polypeptide (GIP)[43]. GIP was later found to stimulate
insulin secretion. What was very interesting was that GIP
would only stimulate insulin secretion in the presence of
high blood sugar. This finding has implications in treatment terms since drug that only works with high blood
sugar would be much less likely to cause hypoglycaemia.
Patients, their families and of course doctors and other
health care professionals all fear hypoglycaemia. Garber[44]
refers to the many hospital visits caused by hypoglycaemia and suggests that minimisation of hypoglycaemia
should be a goal for treatment of type 2 diabetes. I would
certainly agree. In a survey insulin accounted for 13.9%
of overall admissions to hospital from adverse drug reactions and oral anti-diabetic drugs 10.7%[45].
Another incretin was discovered in 1985 and called
glucagon-like peptide-1 (GLP-1)[46]. This hormone was
also dependent on high blood sugar level for full action.
Both GIP and GLP-1 act by binding to specific receptors and so release insulin. GLP-1 has another action,
it inhibits gastric emptying and this has been of benefit
in the treatment of diabetic patients because the feeling
of satiety leads to weight reduction. Another beneficial
effect of the reduction in rate of gastric emptying is to
delay absorption of food, a mechanism which improves
blood sugar excursion. GLP-1 also regulates appetite and
food intake through its effect the hypothalamus. A recent
review of the effects of GLP1 on appetite and body
weight with a focus on the central nervous system has
been published[47].
GLP-1 agonists have been shown to stimulate B cell
growth in animals and cell cultures. In humans it is less
clear if these drugs can improve insulin output by regenerating the B cell. It seems less likely that the dipeptidyl
peptidase (DPP)-4 inhibitors could also have an effect on
B-cell re-growth. However an abstract presented at the
Annual American Diabetes Association meeting in 2010
suggested that linagliptin was able to restore beta cell
function in human isolated islets[48]. Vildagliptin has also
been shown to improve beta cell function and glucose
tolerance but also to improve the extensive peri-insulitis
found in the mouse model examined[49].
A very interesting effect of GLP-1 analogue therapy
has been described in obese type 2 diabetic patients. The
investigators found a reduction in inflammatory macrophages and a reduction in inflammatory cytokines together with an increase in the adipokine adiponectin. The
researchers had previously described a case of psoriasis
that was greatly improved by GLP-1 agonist therapy[50].
The new study does suggest an important beneficial effect of GLP-1 analogue therapy that needs further inves-
as long-term cardiovascular adverse effects also making
surveillance mandatory. Another recently published study
comparing canagliflozin with placebo and sitagliptin produced similar results[37]. A randomised, blinded, prospective Phase 111 study on dapagliflozin as monotherapy in
drug naive Asian patients with type 2 diabetes found that
with the 10 mg dose HbA1c had fallen from a mean of
8.26% to 7.15% as compared to a fall of only 0.29% for
placebo(a difference of 0.82%) Genital infections occurred in 4.5% of patients and Urinary tract infections in
5.3%[38].
The role of these drugs in the treatment of type 2 diabetes is not clear at present but the lack of risk of hypoglycaemia and the weight reduction suggest that there is
a place for them in certain patients who are inadequately
controlled and in whom an extra 0.5% or more reduction
in blood sugar would be of benefit in bringing the patient
into the acceptable blood sugar range.
METFORMIN
The reason for metformin as first line pharmacological
treatment is based on many studies suggesting that metformin is weight neutral or associated with very modest
weight loss as compared with sulphonylureas which cause
slight weight gain initially. Also, in experimental conditions reperfusion after myocardial infarction is reduced
by sulphonylureas. As long ago as 1971 the University
Group Diabetes Program[39] showed that tolbutamide,
a first generation sulphonylurea, was associated with an
increased cardiovascular risk in diabetes. The UKPDS
trial[40] suggested that metformin has a protective effect
on mortality. Roumie et al[41] examined the comparative
effectiveness of sulphonylurea and metformin monotherapy on cardiovascular events in type 2 diabetes mellitius. This was a very large retrospective cohort study
examining cardiovascular outcomes. The crude rates of
composite outcome were 18.2 per 1000 person years in
the sulphonylurea users and 10.4 per 1000 person years
in the metformin group. A wonderful editorial in the
same edition of the Annals of Internal Medicine by Nissen[42] entitled “Cardiovascular effects of Diabetes Drugs;
Emerging from the dark ages”, likens the dark ages after
the fall of the Roman Empire to the time between the
University Group Diabetes Program in 1972[39] which
showed that treatment for diabetes with phenformin or
tolbutamide was associated with increased cardiovascular risk, and 2012. The article explains why there is still
uncertainty about the effect of sulphonylureas and cardiovascular events. Nissen[42] suggests that the study is
hypothesis generating rather than definitive and that high
quality evidence is still missing “Continued darkness is
not an acceptable option” he concludes.
INCRETINS
It has been known for many years that intravenous
glucose will not stimulate insulin secretion to the same
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tigation[51]. A good review on the extrahepatic effects of
GLP-1 receptor Agonists has just been published[52].
Bunck et al[61] showed similar results compared to glargine.
In their study combined glucose and arginine stimulated
C peptide secretion was 2.46 fold greater after 52 wk of
exenatide treatment compared with insulin glargine treatment with a non significant (P = 0.55) 0.8% reduction in
HbA1c as compared to a -0.7% reduction in the glargine
group. Four weeks after cessation, the beta cell function
returned to pre treatment levels.
Exenatide, was compared to glimepiride in patients
who were not controlled on metformin alone[62]. About
1000 patients were divided into 2 groups and studied on
average for 2 years although some went on for 42 mo. At
the end of 3 mo both groups had decreased HbA1c from
around 7.4% to 6.8% but by 36 mo the glimperamide
group had gone back to a HbA1c of more than 7.3%
whereas the exenatide group, although increasing their
HbA1c slowly over the 3 years, was significantly lower at
a level of just over 7.2%. Body weight fell in the exenatide group by 3.32 kg and rose in the glimperamide group
by 1.15 kg. Systolic blood pressure (BP) decreased in the
exenatide group by 1.9 mmHg with no change in the
Glimpereride group. Less patients in the exenatide group
experienced a hypoglycaemic episode. In the first 6 mo
49 patients in the exenatide group discontinued mostly
due to gastrointestinal side effects as compared to 17 in
the glimepiride group (P = 0.001) Buse et al[63] examined
whether twice daily exenatide injections reduced HbA1c
levels more than placebo in patients receiving Glargine
insulin. HbA1c decreased by 1.74% in the exenatide
group as compared to 1.04% in the placebo group over a
30 wk period. Hypoglycaemia was similar in the 2 groups
and 13 treatment patients and 1 placebo recipient discontinued the study because of adverse events, nausea and
vomiting being the main problems.
DEVELOPMENT OF GLP-1 FOR THE
TREATMENT OF DIABETES
Exenatide is a GLP-1 receptor agonist. It is a 39 amino
acid peptide produced in the saliva glands of the Gila
monster lizard[53] it has 53% amino acid homology to
full length GLP-1 and it binds with greater affinity than
GLP-1 to the GLP-I receptor in GLP-1 receptor expressing cells[54]. DPP-4 cleaves peptides and is responsible for
the rapid breakdown of GLP-1. DPP-4 does not denature
exenatide because of the slight amino acid differences and
in human studies the half life ranges from 3.3 to 4 h[55].
Exenatide (Eli Lilly) is now in clinical use in many countries for the treatment of diabetes. It must be given an
hour before meals on a twice a day basis. Many trials have
reported that the drugs cause about a 1% reduction in
HbA1c and reduction in body weight of 5.3 kg at the end
of 3 years of treatment[56]. The dropout rate is about 20%,
many patients refusing treatment because of nausea.
EXENITIDE
Attempts have been made to prolong the action of exenatide using a polylactide glycolide microsphere suspension
so that the drug can be given weekly. Kim et al[57], in a randomised placebo-controlled phase 2 study examined the
effect of exenatide long acting release, a long acting release exenatide formulation, found that a weekly dose for
15 wk in patients with type Ⅱ diabetes resulted in a 1.4%
reduction in HbA1c, suggesting that once a week formulation may be as good as, if not better than, twice daily injections of exenatide. In particular there were no dropouts
in the trial due to adverse events. Liraglutide is a long acting GLP-1 analogue with attachment of a C-16 free fatty
acid derivative. The free fatty acid derivative promotes
non-covalent binding of liraglutide to albumen thereby
increasing plasma half life. A recent study comparing liraglutide once a day with exenatide twice a day found that
liraglutide improved HbA1c significantly more (-1.12% viz
-0.79%) and was generally better tolerated[58]. The study
has demonstrated that glycaemic improvement and weight
reduction are independent of each other. This fits in with
other studies which suggest that the weight loss is not, in
itself, the cause of the improved blood sugar control[59].
In a recent paper Derosa et al[60] examined the effect
of exenatide on beta cell function. The authors used the
homeostasis model assessment beta cell function index
as well as assessing pro-insulin and insulin with arginine
stimulation under clamp conditions. The results suggested that beta cell function was improved by exenatide.
However a caveat, HbA1c was significantly better after
the 12 mo of exenatide as compared to placebo. It is
well known that hyperglycaemia is toxic to the beta cell
hence the improved glucose might have been responsible
for the beta cell improvement rather than the drug itself.
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LIRAGLUTIDE
At the beginning of 2012 the FDA approved the marketing of extended release exenatide (Bydurion). The drug is
given weekly by injection. Liraglutide is a human GLP-1
analog given by once daily injection with a good safety
record and HbA1 lowering effect similar to the other
GLP-1 agonists. A 2-year report on safety, tolerability and
sustained weight loss over 5.2 years with once daily liraglutide has been published[64]. Two hundred and sixty eight
of 398 people who entered the extension of the original
20 wk trial completed 2 years. Weight loss was 7.8 kg
from screening and was maintained. There were improvements in BP and lipids. Patients with diabetes however
were excluded from taking part in this trial. The Duration
Trial 6[65] reported on a study comparing daily liraglutide
to weekly extended release exenatide. This was a 26 wk
trial with more than 400 patients in either arm. Liraglutide
was associated with a greater change in HbA1c (-0.48%
viz 1.28%). Nausea was more common in the liraglutide
group (21% viz 9%) and also vomiting (11% viz 4%) 5%
of patients allocated to liraglutide discontinued the treatment as compared to 3% allocated to exenatide because
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Tomkin GH. New treatments for type 2 diabetes
of adverse events. The results suggest that the patient
might be allowed to choose whether to have a drug which
is injected daily but with no diluting procedure before the
injection or a weekly injection with less blood sugar lowering effect but less side effects. Non-alcoholic steatosis has
become a problem in type 2 diabetes. The LEAN study is
currently examining whether liraglutide will improve nonalcoholic steatohepatitis outcome[66].
group. HbA1c of < 53% was achieved in 39.47% and
32% receiving Taspoglutide 10 mg, 20 mg and HbA1c <
48 in 18%, 24%, and 14% of patients or glargine insulin
respectively. Lower fasting blood sugars were achieved
by glargine insulin. Serious hypersensitivity reactions occurred in 2 patients on Taspoglutide. However confirmed
hypoglycaemia was less with the study drug (0.3%, 0.9%
viz 3.1%) and weight loss was greater on Taspoglutide (-3.3
and -4.1 kg). Withdrawals due to adverse effects occurred
in 9%, 13% on Taspoglutide and in 1% on the glargine
insulin. An addendum to the paper states that Roche
has now stopped the development of the drug. Ibsen is
currently pursuing further investigations. Rosenstock et
al[72] examined the fate of Taspoglutide once a week vs
Exenatide for type 2 diabetes. The doses used were again
10 mg or 20 mg as compared to twice daily exenatide 10
μg. Reduction in HbA1c was -1.24 with 10 mg and -1.31
with the 20 mg as compared to exenatide from a starting
HbA1c of 8.1%. Withdrawals were higher in the study
drug patients and the authors conclude that even though
Taspoglutide caused lower blood sugars the level of side
effects was unacceptable.
Albiglutide is a long acting subcutaneous albumenbased fusion of GLP-1 [73]. In February 2009 Glaxo
SmithKline (GSK) began phase 3 studies in type Ⅱ
diabetes. Albiglutide is a GLP-1 mimetic generated by genetic fusion of a DPP-4-resistant GLP-1 dimer to human
albumin[74]. The formulation was originally developed
by Human Genome Sciences (HGS) and named Albugon, GSK having bought the drug in 2004 for all human
therapeutic and prophylactic applications of Albiglutide.
In 1999 Centeon (now Aventis Berring) granted Principia
(now HGS) world wide rights to its recombinant fusion
proteins and its related yeast technologies[75].
LIXISENATIDE
Lixinitide is another potent, selective, once daily GLP-1
agonist. A randomised placebo controlled double blind
trial examined lixisentide daily injection in Asian patients
with type 2 diabetes insufficiently controlled on basal
insulin with or without sulphonylureas[67]. This was a 24
wk study. These patients were not obese body Mass Index 25.3 kg/m2. Eighty-two percent of patients reached
and stayed on the maintenance dose of lixisenatide (20
μg once a day). There was a significant reduction in
HbA1c compared to controls. The difference at the end
of the trial was 0.88%. There was no significant change
in weight compared to controls. The incidence of serious
side effects were similar in both groups. Two patients in
the lixisenatide group experienced cerebrovascular infarction. Forty-two percent of study drug patients experienced hypoglycaemia as compared to 24% on placebo.
Fonseca et al[68] examined efficacy and safety of once
daily lixisenatide at different doses. HbA1c was reduced
by 0.66% compared to placebo. Postprandial and fasting
blood sugars were significantly lower in the treatment
group. In a study by Kapitza et al[69] lixisenatide once daily
was compared to liraglutide once daily in patients with
type 2 diabetes insufficiently controlled on metformin.
This was only a 28 d study but the results showed that
liraglutide controlled fasting blood glucose better than
lixisenatide but postprandial blood sugar was better controlled by lixisenatide. A review discussing the place of
this GLP-1 agonist as an add on therapy to basal insulin
has recently been published[70].
ANTIBODIES TO GLP-1 AGONISTS
Therapeutic proteins/peptides with structural similarity
to endogenous proteins/peptides often have unwanted
immunogenicity. Antibodies to the GLP-1 agonists have
been described and may inhibit the action of the agonist.
The role of antibody formation to the various agonists
on the market at present are uncertain. A study by Buse
et al[76] in 2011 suggested that antibodies to liraglutide did
not inhibit efficacy however antibodies to exenitide, if
they were high, was associated with a smaller HbA1c reduction. Antialbiglutide antibodies developed in 2.5% of
patients in an 8 wk trial.
TASPOGLUTIDE
Ipsen Roche had another GLP-1 analogue under review
called taspoglutide. This is a GLP-1 analogue which has
a prolonged action and is in phase Ⅱ trials. The drug
has been shown to improve diabetes control and lowers
body weight in subjects with diabetes. In a study involving
once a week injections in 306 type 2 diabetic subjects who
were already on Metformin, 8 wk treatment was associated with a reduction in HbA1c. The highest dose gave
an HbA1c reduction of 0.9% and a weight reduction of
1.9 kg as compared to placebo. Nauck et al[71] report on
a 24 wk study using a 10 mg or a 20 mg dose of Taspoglutide, comparing once a week dosing to daily glargine
insulin. One thousand and forty-nine patients were randomised into 3 groups. Withdrawal rates were 21% for
each of the Taspoglutide groups and 9% for the glargine
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GLP-1 AND THE CARDIOVASCULAR
SYSTEM
Endothelial dysfunction is a common finding in diabetes
and an early marker of atherosclerosis. GLP-1 has been
shown to improve endothelial dysfunction[77,78]. GLP-1
exerts a cardio-protective effect against ischaemic damage and heart failure. Diabetes is associated with an increased risk of atherosclerosis and myocardial infarction.
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Tomkin GH. New treatments for type 2 diabetes
Ischaemic preconditioning is a protective mechanism
by which the heart may protect itself from prolonged
ischaemia. The University Group Diabetes Programme
report[39], more than 40 years ago, suggested that tolbutamide might increase myocardial infarction and mortality. Glibenclamide has been shown to affect ischaemic
preconditioning but trials have not shown beyond doubt
that it is associated with increased myocardial infarction.
However drugs that inhibit the K ATP channel opening,
such as glibenclamide, are related to loss of ischaemic
preconditioning[79-81]. GLP-1 receptors are found in the
heart. Increased glucose uptake by the cardiac myocyte
is beneficial in protecting the heart from ischaemia
changes[82]. Studies in situ and ex-vivo suggest a beneficial
effect on the heart muscle when under ischaemic stress.
Bao et al[83] examined the effect of albiglutide in rats after
myocardial ischaemia reperfusion injury. They measured
cardiac glucose uptake and cardiac metabolic flux. They
found enhanced glucose uptake and reduced myocardial
infarct size and improved cardiac function. It has yet
to be shown if this effect also occurs in humans and if
myocardial infarct size and mortality will be reduced by
GLP-1 agonists. DPP-4 inhibitors have been less well
studied in cardiac ischaemic preconditioning. In a study
by Rahmi et al[84] rapaglinide, a sulphonylurea like drug,
inhibited ischaemic preconditioning as measured by
stress testing in patients with type 2 diabetes who already
had evidence of coronary atherosclerosis. Vildagliptin,
a DPP-4 inhibitor, did not alter preconditioning in 72%
of patients whereas 83% of the repaglinide patients had
ischaemia earlier in their stress test.
found in 18% of papillary thyroid carcinoma. The authors
speculate on the consequences of long term stimulation
of these GLP-1 receptors. They suggest that prospective
studies need to be done to exclude an increase in papillary
and medullary carcinoma in the thyroid.
DPP-4 INHIBITORS
These drugs act by inhibiting the enzyme that breaks
down GLP-1, thus increasing the level of GLP-1 in the
blood stream. They are however not able to raise the
GLP-1 levels to levels found after injection of GLP-1
agonists and therefore their hypoglycaemic efficacy is
less than that of GLP-1 agonists. Sitagliptin, vildagliptin,
saxagliptin and linagliptin have already been approved in
the United States and in Europe. An excellent systematic
review and meta-analysis has been published in the British
Medical Journal in 2012[90]. Compared with metformin,
DPP-4 inhibitors were associated with a smaller decline in
HbA1c and a lower chance of attaining a HbA1c goal of
less than 7%. As a second line treatment DPP-4 inhibitors achieved a smaller decline in HbA1c than the other
hypoglycaemic drugs. There was however, no significant
difference in attaining an HbA1c of less than 7% when
compared to sulphonylureas. They were less effective
in lowering body weight when compared to metformin.
When added to metformin they had a favourable weight
profile compared to metformin and sulphonylureas or
pioglitazone but not when compared to GLP-1 agonists.
Hypoglycaemia was less common when a DPP-4 inhibitor
was added to metformin as compared to a sulphonylurea
added to metformin. There is evidence to suggest that the
DPP-4 inhibitors are more effective in lowering glucose
in Asians than non Asians[91]. A one year follow up of
DPP-4 inhibitors vs sulfonylureas on top of metformin
has been published recently[92]. Patients with prior metformin therapy received a dual combination of metformin
with either DPP-4 inhibitor or sulfonylureas. There was
no significant difference in either body weight or HbA1c.
Hypoglycaemia was significantly less in the patients taking DPP-4 inhibitors. These patients had significantly less
transitory cerebral ischaemic attacks whereas other cardiovascular events were of borderline significance.
There are 6 DPP-4 inhibitors (e.g., Sitigliptin, Linagliptin, Vildagliptin, Alogliptin, Saxagliptin, Teneligliptin)
on the market minor variation in their chemical composition have not been translated to particular benefit
although it should be noted that linagliptin is mostly excreted in pathways other than the kidney and hence dosage does not have to be reduced in moderate renal failure.
Vildagliptin, a DPP-4 inhibitor which increases circulating GLP-1 levels, has been shown to ameliorate the
deposition of amyloid beta and tau phosphorylation in
a streptozotosin induced animal model of diabetes[93]. A
study by Omar et al[94] using a high fat diet induced obesity model in mice of advanced age has demonstrated that
Vildagliptin confirms other rodent models of diabetes in
preserving beta cell mass mainly through inducing beta
cell proliferation and reducing beta cell apoptosis[94-96].
GLP-1 AND THE PANCREAS
Pancreatitis has been described in patients using GLP-1
agonists. A report in 2010 stated that 8 cases during
clinical development and 36 post marketing reports are
available[85]. A recent report[86] examined a large United
States health insurance claims database and could find
no increased risk of acute pancreatitis using twice daily
exenatide. However there were several limitations to the
study and it was a pity that other GLP-1 agonists were
not investigated at the same time but the study was funded by Amylin and Eli Lilly. Stimulation of GLP-1 receptors that are found in the exocrine pancreas might lead to
overgrowth of the epithelial cells in the small ducts causing pancreatitis through obstruction. A worry has been
raised that GLP-1 agonists may induce metaplasia and
premalignant changes[87,88].
GLP1 AND THE THYROID
The thyroid contains GLP1 receptors and Gier et al[89]
also found coincident immunoreactivity for calcitonin and
GLP-1 receptors in both medullary thyroid carcinoma
and C cell hyperplasia. C cell carcinoma of the thyroid
has been seen in animals dosed with GLP-1 agonists and
can be explained by the finding of GLP-1 receptors in
the thyroid[89]. GLP-1 receptor immuno-reactivity was also
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Tomkin GH. New treatments for type 2 diabetes
Omar et al[94] found that Vildagliptin improved glucose
secretion in response to oral glucose. Beta cell area was
not significantly altered by Vildagliptin treatment in these
mice but peri insulitis was prevented by Vildagliptin. Sitagliptin has also been shown to protect against amyloid
associated beta cell loss but its effect was not different to
that of Metformin[97].
The binding modes of these drugs has recently been
investigated[98]. Based on their binding sites the authors
divided the drugs into 3 categorise, Vildagliptin and
Saxagliptin, Alogliptin and Linagliptin, Sitagliptin and
teneligliptin. It is not clear whether these different binding modes have clinical relevance but may help in the
development of better inhibitors in the future. Unlike
GLP-1 agonists the DPP-4 inhibitors do not pass the
blood brain barrier and have no effect on satiety, nor
do they effect gastric emptying. Although the different DPP-4 inhibitors have some differences including
potency, half lives and metabolism there does not seem
to be any meaningful difference in their ability to lower
blood sugar and this is probably why there are virtually
no head to head studies (one head to head study showed
no difference between saxagliptin and sitagliptin when
combined with metformin[99]. A good review of the differences has been written by Capuano et al[100]. Most of
the DPP-4 inhibitors can be administered once daily but
Vildagliptin needs to be given twice daily. Saxagliptin is
mainly metabolised by CYP3A4/5 isoforms to a major
active metabolite 5-saxahydroxygliptin. It is suggested
that the dosage of saxagliptin be modified if co administration with CYP3A4/5 inducers such as rifampicin or
inhibitors such as ketoconazole.
and achieving individualised targets over 24 wk for elderly patients (over 70 years of age with type 2 diabetes).
The patients who were treated with vildagliptin achieved
a 0.6% reduction in HbA1c from a baseline of 7.9% as
compared with placebo. There were no tolerability issues
as compared to placebo, hypoglycaemic events were 2.2%
in the vildagliptin arm and 0.7% in the placebo arm. Individualising goal HbA1c is thought to be appropriate
particularly in the frail elderly[104]. The benefit of reducing
HbA1c by less than 1% in this age group is uncertain.
There seems no doubt that in the frail elderly hypoglycaemia is a very serious threat to health[105,106]. Macrovascular
disease/events seem to respond better to blood pressure
and lipid interventions than to blood sugar lowering at
least in the short term[107] but microvascular damage and
retinopathy prevention, particularly in patients who already have significant damage, should make the Physician
consider carefully the probable benefit of tighter blood
sugar control. Under these circumstances one might not
choose a DPP-4 inhibitor since they work better in the
higher blood sugar range and are less likely to result in
the achievement of a HbA1c of 6.5% (48 mmol/L). The
efficacy and safety of vildagliptin in patients with type 2
diabetes inadequately controlled on Metformin and sulphonylurea suggests that a mean HbA1c of 8.75% can
be improved by about 0.75% as compared to placebo[108].
It is such a pity that the GLP-1 agonists work best at
high HbA1c levels and are less effective in reduction of
HbA1c as the HbA1c gets near to target. However in this
trial 25% more patients reached a target of 7% as compared to controls(38.6% viz 13.9%).
SAXAGLIPTIN
SITAGLIPTIN
The 4-year safety of saxagliptin has recently been published[109]. No new safety issue findings appeared during
the 4 years of treatment alone or with metformin and hypoglycaemia did not increase the risk of hypoglycaemia.
The cardiovascular safety of diabetic drugs continues to
raise concern[109]. Saxagliptin was examined by Scirica et
al[110]. They randomised 16492 patients with type 2 diabetes who had a history of or who were at risk for cardiovascular events, to receive Saxagliptin or placebo and followed them for a median of 2.1 years. The HbA1c at the
beginning of the study was 8.0% and at the end of the
study the HbA1c in the Saxagliptin arm had decreased to
7.5% and the placebo arm to 7.8%. A surprising finding
was that more patients in the Saxagliptin group were hospitalised for heart failure but otherwise the cardiovascular
end point results were similar between the two groups.
Hospitalisation for hypoglycaemia occurred infrequently
and was similar in the two groups but significantly more
patients in the saxagliptin group reported at least one
hypoglycaemic event. Thus this 2-year study gives little
support for the use of saxagliptin in these patients.
Insulin glargine vs sitagliptin another DPP-4 inhibitor was
studied by Aschner et al[101]. About 250 patients in each
group were studied for more than 6 mo. At the start patients were already on metformin which was continued
during the study. HbA1c was significantly lower in the
glargine group. There were more hypoglycaemic episodes
and slight weight gain in the glargine group where as
there was slight weight loss in the Sitagliptin group. A
recent study compared the effect of sitagliptin or glibenclamide in addition to metformin and pioglitazone on
glycaemic control and beta cell function[102]. Body weight
reached was lower with sitagliptin. Fasting plasma insulin
and homeostasis model assessment of insulin resistance
with glibenclamide were significantly increased with glibenclamide and decreased with sitagliptin. Sitagliptin did
not change the homeostasis model assessment of beta
cell function but the value was significantly increased
by glibenclamide. Both glibenclamide and sitagliptin increased C-peptide.
VILDAGLIPTIN
LINAGLIPTIN
A 24 wk study in elderly patients was recently publis­
hed[103]. The study investigated the feasibility of setting
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Linagliptin is a once a day oral DPP-4 inhibitor. It is an
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October 15, 2014|Volume 5|Issue 5|
Tomkin GH. New treatments for type 2 diabetes
orally active small molecule which was licensed in United
States in 2011. It is mostly excreted in the faeces and
there are no clinically relevant alterations in linagliptin
pharmokinetics resulting from renal or liver impairment[111]. A recent study has confirmed that renal impairment has no clinically relevant effect on the long term
exposure of linagliptin in patients with type 2 diabetes[112].
A 2-year efficacy and safety study of linagliptin compared to glimepiride in patients inadequately controlled
on metformin was reported recently[113]. More than 1400
patients were divided into two groups. HbA1c at the
end of the study was similar in the two groups but there
was less hypoglycaemia and there were significantly less
cardiovascular events (1 vs 2). Hypoglycaemia is not usually a problem in the treatment of type 2 diabetes but
recently has been suggested to be a therapeutic concern.
The efficacy and safety of Linagliptin in subjects with
type 2 diabetes was analysed by Del Prato et al[114]. Pooled
analysis of data from 2258 subjects in 324 wk phase 3
studies. Oral linagliptin or placebo as monotherapy added
on to metformin or added on to metformin plus a sulphonylurea were the treatments investigated. Although
linagliptin was effective the patients had a mean HbA1c
of 9.0% and the level of HbA1c only dropped to 8.3%
still unacceptably high for many patients. DPP-4 inhibitors unfortunately work less well the lower the starting
HbA1c[102]. A study of linagliptin in patients aged over 70
years found that HbA1c was lowered by 0.64% from 7.8%
to 7.2% with a safety profile similar to placebo. Whether
long term studies in this age group will show benefit in
measurable outcome is speculative at this time.
glucose uptake by the cardiac myocyte is beneficial in protecting the heart from ischaemia changes[118]. Matsubara
et al[119] examined 44 patients with coronary artery disease
and uncontrolled diabetes (HbA1c > 7.4%). Sitagliptin
or aggressive conventional treatment was compared after
6 mo. Endothelial function was significantly improved in
the sitagliptin group with no difference in fasting blood
sugar at the end of the trial but a reduction in HbA1c of
0.6% in each group. C-reactive protein (CRP) reduced
significantly in the sitagliptin group with a significant correlation between the CRP and the vascular reactivity but
not with HbA1c.
DPP-4 INHIBITORS AND THE PANCREAS
Butler et al[120] examined the pancreata of 7 individuals
treated with sitagliptin and 1 with exenatide compared
with 12 individuals with type 2 diabetes treated with other
agents, and 14 non-diabetics. There was an increase in the
number of pre-malignant lesions and marked alpha cell
hyperplasia with glucagon expressing micro adenomas
and a glucagon expressing neuroendocrine tumour in one
of the eight. Because the number of diabetics who were
not on treatment with DPP-4 based therapy were so few
the evidence is insufficient for alarm but the evidence for
caution and vigilance in the next number of years is clear
and persuasive.
Sero negative polyarthropathy has been recorded
with the use of DPP-4 inhibitors. Three patients were
described by Crickx et al[121] and one case by Ambrosio et
al[122]. The acute arthritis is not perhaps surprising since
DPP-4, also named CD 26 is expressed on many cells involved in the immune process.
ALOGLIPTIN
Alogliptin seems to have much the same characteristics
as the other DPP-4 inhibitors on the market, A useful
review has recently been published[115]. Another large
study specifically looking at cardiovascular disease in
type 2 diabetic patients has been reported[116]. More than
5000 patients who had type 2 diabetes and either an
acute myocardial infarction or unstable angina requiring
hospitalisation within the previous 15 to 90 d received
allogliptin or placebo in addition to existing antidiabetic
and cardiovascular drug treatment. HbA1c at the start of
the trial was 8.0% and at the end of the study had come
down to 7.7% as compared to 7.97% in the placebo
group. Hypoglycaemia was similar in the two groups.
Again this large study makes one question the value of
the addition of the DPP-4 inhibitor which was associated with such a modest drop in HbA1c.
CONCLUSION
New treatments for diabetes are coming on line but
prevention and treatment of obesity through increased
exercise and reduced calorie intake still seems the best
option in most patients with type 2 diabetes. Those with
insulin deficiency have new options which are exciting as
they demonstrate new approaches to treatment but their
glucose lowering effects are modest and mostly most effective when blood sugars are high thus of less use when
blood sugars are near to, but not at, target in spite of a
combination treatment.
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P- Reviewer: Apikoglu-Rabus S, Conteduca V, Kumar KVS
S- Editor: Wen LL L- Editor: A E- Editor: Liu SQ
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